JPS6248796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for a sintering machine.

Generally, the ignition device of a sintering machine uses a burner to inject and burn heavy oil, coke oven gas, or a mixed gas of coke oven gas and blast furnace gas, etc. onto the upper surface of the sintering raw material layer charged and deposited on a pallet. let me,
It is used to combust the coke in the sintering raw material through the joint action of the combustion flame and high-temperature hot air obtained at that time.

FIG. 1 shows a sintering machine in which the ignition device of the present invention is installed. In the figure, 1 is a pallet, 2 is a wind box, and 3 is an ignition device, which mainly consists of an ignition furnace 3a and a burner 3b. 4 indicates a bedding hopper, and 5 indicates a raw material hopper.

Figure 2 shows a typical sintering machine ignition system that has been used in the past, and consists of a group of burners 3b, each consisting of a set of burners arranged in multiple rows in the direction of pallet movement. are doing.

Such conventional ignition devices have the drawbacks of uneven burning and poor fuel consumption. Figure 3 shows the distribution of ignition strength in the width direction of the pallet when a conventional ignition system is used, and there is a clear difference in ignition strength between directly below the burner, which shows each peak value, and at an intermediate position. , which causes uneven burning. In such a case, it is generally necessary to adjust the combustion rate of the burner 3b based on the weakest point of ignition strength to prevent uneven burning, which results in the problem of increased energy usage. be. Moreover, since the ignition strength of each burner is different, it is almost difficult to obtain a uniform ignition strength distribution in the width direction of the pallet.

In addition, in the conventional ignition system, the ignition furnace 3
Due to the high furnace height of 1500 mm on average, the distance from the burner tip to the surface of the sintered raw material layer tends to be long, which tends to increase energy loss.Additionally, the natural dissipation of heat due to the enlargement of equipment also occurs. The problem is that the energy loss becomes even bigger.

On the other hand, recently, an ignition device has been proposed, disclosed in Japanese Patent Application Laid-Open No. 57-37685, which is provided with a single mixing combustion chamber and has a slit-shaped combustion gas discharge port. This device had the following drawbacks because what was blown out from the slit-shaped outlet was not a flame but a type of high-temperature exhaust gas.

(1) Since the mixing chamber becomes red hot, the burner chip, which serves as the combustion gas discharge port, is easily deformed, making it difficult to obtain a stable frame, making it difficult to ignite uniformly in the width direction of the pallet.

(2) In order to prevent the slit-shaped burner chips from deforming, special materials are required, and the structure becomes complicated, resulting in high equipment costs.

(3) It is difficult to achieve complete combustion in the above mixing chamber;
Unburned gas is likely to be discharged and cause ignition failure.

(4) Furthermore, like the existing equipment, the ignition furnace is large, so energy loss cannot be avoided, and the furnace structure is quite complex, requiring a structure with high support strength, which increases equipment costs.

Furthermore, when such an ignition device is applied to a sintering machine, as shown in FIG. 8, excessive ventilation occurs at both ends, resulting in uneven burning. Therefore, it has been proposed to divide the burner, but when the nozzle hole is configured with a slit hole in this way, uniform ignition is difficult due to deformation of the burner chip, and it is still difficult to ignite the burner evenly. There is a problem in that it is not possible to prevent uneven baking in the side portions with excessive ventilation.

The present invention was made in view of the problems of the prior art described above, and an object of the present invention is to provide an ignition device that prevents uneven burning due to excessive ventilation at both ends and enables uniform ignition.

The invention will now be explained with reference to the drawings.

4 to 9 show one preferred embodiment of the multi-hole flame injection ignition device according to the present invention, and the illustrated ignition device includes a burner body Bb and a burner tip Bt.

In the burner body Bb, a fuel gas pipe 6 and a combustion air pipe 7 are provided extending substantially parallel to each other in the width direction of the pallet, and a fuel gas supply pipe 8 and an air supply pipe 9 are provided in the same way. The gas pipe 6 is provided extending in the width direction over the entire width of the gas pipe 6, and is connected to the gas pipe 6 through short pipes 10 and 11 at multiple locations in the pipe axis direction.
and gas supply pipe 8, and air pipe 7 and air supply pipe 9.
are individually communicated. The fuel gas pipe 6 and the air pipe 7 are constituted by concentric double pipes, and coke oven gas etc. are passed through the fuel gas pipe 6 forming the central passage 6a, while forming an annular passage 7a. Air is made to flow through the air pipe 7.

In the central passage 6a of the fuel gas pipe and the annular passage 7a of the air pipe, rectifying plates 13 and 14 each having a large number of through holes 12 are installed so that they can be inserted and removed. It plays the role of distributing the flow.

A fuel gas burner passage 1 extends from the fuel gas pipe 6 and the combustion air pipe 7 in the pallet width direction.
5, and protrusions 6' and 7' forming air burner passages 16 and 16', respectively, protrude in the radial direction, and a flange 17 is provided at the tip of the protrusion 7'.

The burner tip Bt includes the burner body Bb above.
Gas nozzle passages 18 and air nozzle passages 19, 19' corresponding to the fuel gas burner passages 15 and air burner passages 16, 16' are provided, respectively, and a large number of nozzle holes 20, 20', 21, 21' are opened as shown in FIG.
A flange 22 is protruded from the upper end of the Bt and is detachably attached to the flange 17 via bolts 23.

The fuel gas nozzle holes 20, 20' in the burner chip Bt are open to both sides outward, and the air nozzle holes 21,
21', on the other hand, is opened inward, and the injection directions of both are formed to intersect with each other. Moreover, each nozzle hole 20, 2
A large number of combinations of 0', 21, 21' are arranged in the tube axis direction across the width of the pallet at intervals of, for example, about 10 to 20 mm, as shown in FIG.

As mentioned above, the nozzle holes 20, 20', 21,
By arranging the 21' in pairs (with the injection directions intersecting each other), the fuel gas and air are injected through the small-diameter holes, preferably at right angles, compared to conventional burners. ,
The flame becomes a short flame, which allows the upper surface of the sintered raw material layer on the pallet to be brought closer to the burner chip Bt.

However, the nozzle holes 20, 20', 21,
If the diameters of the holes 21' are the same, there is a problem in that the amount of passing air is distributed in the width direction of the pallet as shown in FIG. Therefore, the nozzle holes 20, 20', 21, 2
1' is configured to have a hole diameter that gradually becomes larger at the ends than at the center, thereby enabling uniform ignition in the width direction.

In order to gradually increase the diameter of the nozzle holes at both ends, depending on the increase in air permeability, use three or more types of hole diameters, including the hole diameter in the center, if possible, with a finer variety of hole diameters, increasing toward the ends. It is better.

For this reason, as shown in Fig. 9, depending on the distribution of the passing air volume in the pallet width direction, the nozzle holes 2 in the area corresponding to about 1/5 of each end in the pallet width direction are
0a, 20b, 20'a, 20'b, 21a, 21
The hole diameters of holes b, 21'a, and 21'b are configured to increase successively toward the end.

As an example, when using M gas, the hole diameter of the central nozzle holes 20, 20', 21, 21' is set to 6.0.
mm, next nozzle hole 20a, 20'a, 21a, 2
The hole diameter of 1'a is 7.0 mm, the nozzle hole 20b at the end,
It is preferable that the hole diameters of 20'b, 21b, and 21'b be 8.0 mm.

As a result of the operation according to this example, per day
At a sintering factory with a production capacity of 5000 tons, we were able to reduce the unit heat consumption of the ignition furnace by 1000 Kcal/t-s.

In FIG. 10, parts 25, 26, and 27 in which the hole diameter of the nozzle hole is gradually increased are partitioned or divided by a partition plate 28, and each has a flow rate regulating valve 29 for gas and air amount (see FIG. 7). An example of a configuration in which controllability is improved by providing the following is shown below. Note that 30 indicates a thermal expansion allowance.

Figure 11 shows that when the nozzle holes are divided into parts as shown in Figure 10, the combustion amount of each nozzle hole is different, and the length of the frame is also different. An example is shown in which each of the divided sections is configured to be able to change its vertical angle in order to maximize the temperature.

By making the burner nozzles with different hole diameters movable up and down and tilting in this way, if the sintering operating conditions change, for example, the raw material layer thickness at both ends of the pallet in the width direction is small, so the air permeability may become too high. However, by increasing the hole diameter and adjusting the elevation of the burner, the accuracy of uniform ignition in the width direction of the pallet can be further improved.

Further, even when the layer thickness increases or decreases not only at both ends in the width direction of the pallet but also throughout the pallet, good ignition control can be performed in accordance with the layer thickness.

Furthermore, the contact area between the surface of the sintered raw material and the tip of the frame can be varied by tilting the burner in response to changes in the layer thickness, pallet speed, raw material properties, and moisture content in the raw material, resulting in uniform sintering. In addition to further improving ignition accuracy, significant effects such as improved sintered ore quality and yield, and fuel savings can be obtained.

By providing a fuel gas regulating valve and a combustion air regulating valve for each of the burners having different hole diameters, the above-mentioned effects associated with the lifting, lowering, and tilting operations can be further enhanced.

According to the present invention, it is possible to ignite uniformly at both ends of the pallet in the width direction, and as shown in FIG. 12, uniform ignition strength can be obtained, which eliminates uneven burning and significantly improves yield. This effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional sintering machine, Fig. 2 is a cross-sectional view of a conventional ignition device, Fig. 3 is a distribution graph of ignition strength in the pallet width direction by a conventional ignition device, and Fig. 4 is a bookmarking diagram. sectional view of the ignition device according to the invention,
Fig. 5 is a partially cutaway bottom view of the igniter of the present invention, Fig. 6 is an enlarged bottom view of the nozzle hole of the burner chip, and Fig. 7 is a cross-sectional view of the sinter pellets and part of the igniter. FIG. 8 is a graph showing the distribution of ignition strength in the pallet width direction by the ignition device equipped with the burner chip shown in FIG.
10 is an enlarged bottom view of a nozzle hole of a burner chip showing another embodiment of the present invention, and FIG. 11 is an enlarged bottom view of a nozzle hole of a burner chip according to another embodiment of the present invention. FIG. 12, which is a side view of an exemplary igniter, is a graph showing the distribution of ignition intensity in the pallet width direction by the igniter according to the present invention. Bb...burner body, Bt...burner chip, 1
...Pallet, 2...Wind box, 3...Ignition device, 6...Fuel gas pipe, 7...Combustion air pipe, 8...Fuel gas supply pipe, 9...Combustion air supply pipe, 10,1
1... Short pipe, 12... Through hole, 13, 14... Current plate, 1
5... Burner passage for burning gas, 16, 16'... Burner passage for air, 17... Flange, 18... Gas nozzle passage, 19, 19'... Air nozzle passage, 2
0, 20', 21, 21', 20a, 20a', 21
a, 21a', 20b, 20b', 21b, 21'b
... Nozzle hole, 24 ... Burner hood, 28 ... Partition plate or division part, 29 ... Flow rate adjustment valve, 30 ... Thermal expansion allowance.

Claims (1)

[Claims] 1 A large number of pairs of fuel gas passages and combustion air passages extending in the width direction of the pallet of the sintering machine are provided, and the passages are oriented and open so that the jets of fuel gas and combustion air meet each other. Nozzle holes are provided spaced apart along the length direction of each of the passages, and the diameters of the nozzle holes are made to correspond to the distribution of the air flow rate passing through the raw material layer from the central part in the length direction of the passages to both ends of each of the passages. An ignition device for a sintering machine, characterized in that the ignition device is sequentially increased in size in at least three stages.